653
FXUS63 KFGF 311808
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
108 PM CDT Sun Aug 31 2025

.KEY MESSAGES...

- Dense fog is expected through mid-morning.

&&

.UPDATE...
Issued at 1019 AM CDT Sun Aug 31 2025

Dense fog continues in portions of the Sheyenne River Valley
(namely within Barnes and Griggs counties) into the Red River
Valley. Fog will continue to gradually diminish around the area,
dissipating by noon.

UPDATE
Issued at 656 AM CDT Sun Aug 31 2025

While not all spots in the Dense Fog Advisory are socked in,
especially on the edges of the deck, many are very foggy.
Will keep an eye on the finger of stratus seen on satellite
reaching towards Grand Forks and Thief River Falls, but for now
will keep the headline as it is.

&&

.DISCUSSION...
Issued at 352 AM CDT Sun Aug 31 2025

...Synopsis...

Very weak upper and surface flow continues into this morning
with blocking ridge still over northern MN into ONT and weak
upper circulations to our west and south. One of the weak
circulations will come down out of Canada into eastern ND on
Monday, bringing some shower and thunderstorm activity. While
there are decent probabilities for good instability, shear is
still very weak and not expecting severe impacts. Upper flow
will pick up on Tuesday as a more robust trough digs down out
of Canada. Impacts will depend greatly on the timing of the cold
front that this trough brings, and several solutions have it
past us by peak heating while a few others show the potential
for some stronger elevated cells. Probability of CAPE values
over 1000 J/kg are around 40 percent at best, and shear doesn`t
get too impressive until well after the front passes. Will
continue to hold off on any messaging for storms on Tuesday but
will keep an eye on things.

Of greater certainty is cooler temperatures behind the front,
knocking values down below seasonal averages. Probabilities of
lows less than 32 degrees are still around 20 percent in the
boggy areas of MN, but chances for less than 36 degrees east of
the Red are around 60 percent, so patchy frost is not out of the
question. A bit too soon to message frost headlines as much
will depend on cloud cover, but the cool down from highs in the
80s will be noticeable.

...Fog this morning...

Winds are mostly light but have enough southerly to southeasterly
fetch to bring plenty of moisture north into our CWA. Fog has
already developed from the SD border up towards Devils Lake.
While so far web cams are still rather patchy, there is more
consistency in the high-res ensembles and HREF probabilities
are up to 70 percent for less than a half mile visibility. This
is mostly in southeastern to east central ND, which fits current
observation and satellite trends so far. For now have an
advisory southwest of a Devils Lake to Hillsboro to Fergus
Falls line, but may need to expand depending on how far east the
more dense fog gets in the next few hours.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 104 PM CDT Sun Aug 31 2025

VFR conditions will prevail through at least 09Z, with a low
chance for fog between 09Z-14Z.

Mostly clear skies are forecast today with the exception of
some daytime fair weather cumulus through 00Z. Winds will be
generally out of the south between 5-12kt until around 00Z when
winds lessen and become variable.

While fog is not likely tonight, there is a 20% chance for it to
form within portions of the Red River Valley into Minnesota,
including sites like KGFK, KFAR, KTVF, and KBJI. This fog could
be dense. Fog will start to form around 09Z and diminish by 14Z
if it does form.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.

&&

$$

UPDATE...CJ/JR
DISCUSSION...JR
AVIATION...CJ